Fluid couplings, such as the type commonly used on the ends of flexible hose to selectively connect and disconnect the hose to complete a fluid flow circuit often utilize valves within the couplings to close the coupling to fluid flow prior to disconnection.
Valved fluid couplings may be of the "self-sealing" type wherein valve structure of the coupling fitting automatically closes and opens upon the coupling being disconnected, and coupled, respectively. The most common type of self-sealing valve structure includes axially movable valve components, such as a sleeve or poppet valve wherein relative axial movement between the coupling halves during coupling and uncoupling is utilized to displace the valve structure. As sleeve and poppet type valves usually include ports and flow passages requiring the fluid flow to be transverse, usually perpendicular, to the axis of the coupling passage, such valves produce significant pressure loss within the fluid passing through the coupling, and also produces turbulence and other undesirable characteristics.
Couplings utilizing ball valves have not been widely used in view of several manufacturing and operating deficiencies. While ball valves utilizing a fluid flow bore of a diameter substantially equal to the coupling passage create little flow resistance, prior coupling constructions are unduly large. Further, while a ball valve only need rotate 90.degree. between its full open and full closed positions its operating characteristics do not readily lend themselves to automatic self-sealing operation. Manual control of the ball valves must be coordinated with the state of the interconnection between the coupling halves, and prior art couplings have not successfully combined the high flow capacity, low flow resistance advantages of ball valves with concise coupling construction and safety features which minimize leakage during uncoupling and coupling, and operation.
It is an object of the invention to provide a coupling utilizing a ball valve wherein the high capacity, low flow resistance characteristics of ball valves are utilized to the maximum, and yet, spillage and leakage of the fluid being carried is minimized.
Another object of the invention is to provide a fluid coupling utilizing a ball valve wherein opening of the valve is prevented until a full coupling connection has been made, and uncoupling cannot occur until the ball valve has been shifted to its closed position.
A further object of the invention is to provide a coupling having identical halves wherein each half is provided with a ball valve, and the ball valve of each half cannot be opened until the halves are fully coupled, and the coupled halves cannot be discoupled until both ball valves have been fully closed.
Another object of the invention is to provide a fluid coupling utilizing ball valves wherein fluid leakage during uncoupling is minimized.
In the practice of the invention coupling halves are employed each having a passage, at least one of which receives a rotatable ball valve having a diametrical bore substantially equal to the coupling passage. The ball valve is rotatable 90.degree. between fully open and fully closed positions, and valve positioning is through an actuator which includes an exteriorly accessible manually operated handle. While only one coupling half may be valved, the most common embodiment uses identical coupling halves each valved, and such a coupling is hereinafter described.
The coupling halves are interconnected by axially extending headed projections received within complementary shaped lipped recesses, both of arcuate form and concentrically related to the axes of the coupling halves. Reception of the projections into the recesses, and relative rotation of the coupling halves about their longitudinal axes, interlocks the coupling halves with bayonet type connections and a predetermined relative rotation between the coupling halves must be achieved to produce a fully coupled relationship.
Each coupling half is provided with locking means in the form of an axially displaceable detent pin operated by a cam surface defined on the associated valve actuator. Rotation of the valve from the closed to the open position causes the detent pin to axially extend from a sealing surface defined on the coupling end which is received within a recess defined within the opposed coupling half only if the coupling halves are fully interconnected Thus, the locking pin detent of one coupling half must be aligned with a locking recess within the other coupling half in order to permit rotation of the ball valves from the closed to the open positions, thereby preventing inadvertent leakage in the event the valves could be opened prior to being fully coupled.
Conversely, the locking means presents the coupling halves from being disconnected from each other until the ball valves have been rotated to the fully closed positions.
The sealing surface defined at the coupling end of the halves is substantially tangential to the spherical exterior surface of the associated ball valve wherein the volume of the void within the coupling passage between the ball valve and the sealing surface is minimized, reducing the volume of fluid which may escape during uncoupling of the halves.
As the bore of the ball valves is of a diameter substantially equal to the passage diameter through the coupling halves only negligible resistance is created in the coupling halves by the valve structure, and valves manufactured in accord with the inventive concept permit maximum fluid flow with minimum pressure loss characteristics for a given coupling size.